The invention relates to an assembly of a low-pressure sodium discharge lamp and a feeding apparatus, in which
the low-pressure sodium discharge lamp has a light source, which is arranged in an evacuated outer envelope, whose inner surface is provided with a translucent electrically conducting coating and to which a Swan lamp cap is secured, which has at its base portion insulated contacts, from which current supply conductors extend to the light source, which light source has a discharge vessel which is filled with an ionizable sodium-containing filling,
the feeding apparatus supplies an alternating voltage having a frequency of at least 80 kHz and is provided with a Swan lamp holder, which has at its base portion insulated contacts, one of which is connected to a neutral conductor and another is connected to an above ground conductor of the feeding apparatus. The invention also relates to a low-pressure sodium discharge lamp and a lamp holder suitable for use in the assembly. Such an assembly is known from GB No. 2 134 701 and corresponding U.S. Pat. No. 4,636,691.
The known low-pressure discharge lamp can be operated at an alternating voltage having the frequency of the mains voltage (for example 50 or 60 Hz), but has a higher efficiency if it is operated at a voltage having a frequency of at least 80 kHz.
It has been found that lamps operated at a voltage having such a high freqency have an electric field which disturbs radio reception.
The invention has for its object to provide an assembly of a low-pressure sodium discharge lamp and a feeding apparatus, of which the radio disturbance during operation of the lamp at high-frequency voltage is suppressed, while the lamp can also be used in conjunction with a conventional feeding apparatus supplying an alternating voltage at mains frequency.